\chapter{Introduction to \tls{}}

\label{sec:tlsintro}
\tls{} stands for 'Transport Layer Security' and is the successor of \ssl{},
the Secure Sockets Layer protocol\footnote{described in \cite{SSL3}} designed by Netscape. 
\tlsI{}\footnote{described in {\it RFC 2246}\cite{RFC2246}} is an Internet protocol,
defined by {IETF}\footnote{IETF or Internet Engineering Task Force 
is a large open international community of network
designers, operators, vendors, and researchers concerned with the evolution of 
the Internet architecture and the smooth operation of the Internet. It is open 
to any interested individual.}, 
that provides confidentiality, and authentication layers over any reliable
transport layer. The description, below, refers to \tlsI{} but also
applies to \sslIII{} since the differences of these protocols are minor.
Older protocols such as \sslII{} are not discussed nor implemented in \gnutls{} 
since they are not considered secure today.

\input{layers}

\input{translayer}

\input{record}

\input{alert}

\input{handshake}

\input{tls_extensions}